var StyleLib = new Object();
StyleLib.normal = 0;
StyleLib.clean = 1;
StyleLib.tech = 2;
StyleLib.fresh = 3;
StyleLib.stringifyTheme = function(num) {
	if (num == 0)
		return "normal";
	if (num == 1)
		return "clean";
	if (num == 2)
		return "tech";
	if (num == 3)
		return "fresh";
};
StyleLib.themes = new Object();
StyleLib.themes.normal = {red:255, green:255, blue:255, alpha:1, background:StyleLib.normal};
StyleLib.themes.clean = {red:0, green:0, blue:0, alpha:1, background:StyleLib.clean};
StyleLib.themes.tech = {red:0, green:0, blue:0, alpha:1, background:StyleLib.tech};
StyleLib.themes.fresh = {red:255, green:255, blue:255, alpha:1, background:StyleLib.fresh};

StyleLib.background = function(step, percent, style) {
	if (style == StyleLib.normal) {
		/* don't do anything */
		Presentation.background(null);
	} else if (style == StyleLib.clean) {
		/* apple like design */
		var bkgGrad = Presentation.createLinearGradient(0, 0, 0, -1);
		bkgGrad.addColorStop(0.5, '#000022');
		bkgGrad.addColorStop(0.8, '#000015');
		bkgGrad.addColorStop(0.9, '#000006');
		bkgGrad.addColorStop(1, '#000000');
		Presentation.background(bkgGrad);
	} else if (style == StyleLib.tech) {
		/* techie design, maybe maths background */
		Presentation.background("rgb(255,255,255)");
	} else if (style == StyleLib.fresh) {
		/* fresh design, for non professional presentations */
		Presentation.background(null);
	}
}
